I just thought I'd describe the den we made for the 1st April as the pictures I've got don't.
We hung a washing line from above our heads at the entrance to waist height at the back of the first room. Then we pegged bedsheets along the line, it became a tunnel. When it turned left it became a cardboard tunnel along the foot of the room, it turned right and up some stairs, this part was made of plastic sheets, it was easier to crawl rather than walk.

There was a table at the end of the tunnel. On the right a small entrance to the cinema was made from orange plastic sheeting. Inside it was dark, very low and quite quiet. At the far end a film was projected onto some material hanging underneath a table.

The film showed 3 den building events:
1. A Brutalist Den made October 2nd 2008
2. Mass den building at "Playing in Urban Spaces" a conference at Leeds Metropolitan University, 3rd October 2008
3. Den building at Coney Island, New York, 21st January 2010.

The cinema den was made of:
3 tables
cardboard
black out material
there was also black out material over the stained glass windows
paper
tape
2 pairs of trestle table legs
pegs

There was space for about 7 people. Some people said they really enjoyed the quiet darkness of the cinema den compared to the big front room space where people were chatting and drinking. The exit of the den was to the left of the projection, after leaving people found they could stand up straight in the darkness for a few steps before having to crawl under the table and back down the stairs to get out again.
A film made from images of the March workshops was projected against the side of the bed sheet tunnel.